Many articles are manufactured via a molding of materials into a desired shape. For example, many polymeric articles, including composites containing polymers, are formed via heated molds. One such article may include tires. Tires may be placed into contact with a mold and heated, under pressure, until the rubber within the tire is crosslinked and cured.
Many molds, including tire molds, are heated by a hot water, steam, heated gas, or other heating mediums. Molds are typically made from a metallic material. The metallic material of the mold may be heated through thermal conduction wherein heat is transferred from a heat medium, through the mold, and into the article to be molded. As a result, each portion of the mold typically obtains the same or similar temperature upon heating of the mold to the desired curing temperature. Also, portions of the mold, molding press, peripheral components, and other elements may be unnecessarily heated as these elements do not contribute to heating the article to be molded.
Heating of molds via hot water, steam, heated gas, or other heating mediums typically requires extended periods of down time during which an entire mold is heated to a curing temperature before molding, and cooled to a safe temperature following molding to permit manipulation of the mold to remove a molded article, the totality of which, including cure time, is commonly referred to as “cycle time.” Additionally, heating of molds in such a manner may lead to inefficiency due to loss of heat from the mold to the surrounding environment via thermal convection and thermal conduction. Heat transferred to the surrounding environment may need to be removed via cooling such that workers in the surrounding environment are comfortable and to prevent damage to other equipment.
What is needed is a system and apparatus for heating a mold that minimizes heating and cooling times, allows for application of different mold temperatures at different portions of the mold, and maximizes energy efficiency.